Machine for homogenising a food substance

ABSTRACT

A machine ( 1 ) for homogenising a food substance has: a container ( 10 ) with a side wall ( 11 ) and a bottom wall ( 12 ) delimiting a cavity ( 10 ′); an impeller ( 30 ) with an impelling member ( 31 ) forming an impelling surface ( 31′,31″,31 ′) that is drivable in rotation (r) about a central axial direction ( 30 ′) of the impelling surface ( 31′,31″,31 ′″) for imparting a mechanical effect to the food substance; and a module ( 20 ) which has a housing means ( 22 ′) that contains an inner chamber ( 22,22   a ) and that delimits a seat ( 21 ) for the container ( 10 ), the chamber ( 22,22   a ) containing an electric motor ( 24 ). The electric motor ( 24 ) has an output drive axis ( 24 ′) with a driver device ( 24 ″) configured to drive a follower device ( 35 ) of the impeller ( 30 ). The driver device ( 24 ″) and the follower device ( 35 ) are magnetically coupled through a sidewall ( 11 ) and/or bottom wall ( 12 ) of the container ( 10 ). The driver device ( 24 ″) comprises a ferromagnetic or magnetic field-generating element ( 24   a ) that is arranged to be magnetically coupled to a corresponding ferromagnetic or magnetic field-generating element ( 36 ) of the follower device ( 35 ). The follower device ( 35 ) extends over a predominant part of the bottom wall ( 12 ) of the container ( 10 ) or across a substantial part of the wall ( 12 ) along a diameter thereof. The driver device ( 24 ) extends over a predominant part of a bottom part of the seat ( 21 ) or across a substantial part of the bottom part of the seat ( 21 ) along a diameter thereof. The ferromagnetic and magnetic field generating elements ( 24   a,   36 ) are positioned at extremal or peripheral parts of the follower device ( 35 ) and of the driver device ( 24 ″).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a National Stage of International ApplicationNo. PCT/EP2016/063664, filed on Jun. 15, 2016, which claims priority toEuropean Patent Application No. 15172386.3, filed on Jun. 16, 2015, theentire contents of which are being incorporated herein by reference.

FIELD OF THE INVENTION

The field of the invention pertains to machines for homogenising a foodsubstance, such as frothing milk or a milk-containing substance. Themachine is provided with an impeller for imparting a mechanical effectto the food substance.

BACKGROUND ART

Specialty beverages in which at least a portion is made up of frothed orheated milk are becoming more and more popular. The best-known beverageof this type is a coffee of the cappuccino type. It comprises a liquidportion consisting of coffee topped by a layer of frothed milk which,because of its very much lower density, floats atop the surface of theliquid. In general, preparing one takes time, manipulation operationsand cleaning.

The most customary way of preparing a milk-based froth is to pour thedesired amount of milk into the container, immerse a steam outlet pipefrom a coffee machine in the container, agitating it up and down tointroduce the air needed to form the froth.

There also exists mechanical stirring appliances which are usuallyintended for domestic use for beating froth from more or less viscousfood products such as eggs, ice, juices or the like. These appliancesare usually ill-suited to froth the microbiologically sensitive liquidssuch as milk. Regular cleaning of the tank of the appliance needs to beenvisaged in order to remove any solid food residue. In addition,heating the milk has a tendency to increase the extent to which cookedor burnt proteins are deposited on and adhere to the surfaces. Theexisting appliances are not, for the most part, well suited to reducingthe encrustation of this solid residue, making cleaning troublesome.These appliances also have a stirring and drive mechanism which is fixedand intrudes into the tank, and this presents several disadvantages: theremoval/refitting time is not insignificant, they have a tendency tobecome soiled more quickly, they entail additional cost as a result ofthe multiplicity of components, and the stirring means are difficult toclean.

U.S. Pat. No. 6,318,247 relates to an appliance for preparing hotbeverages or food with stirring such as hot chocolate, for example.Other devices for stirring food products are described in patentdocuments WO 2004/043213 or DE 196 24 648. Stirring systems with amagnetic engagement type are described in documents U.S. Pat. No.2,932,493, DE 1 131 372, U.S. Pat. Nos. 4,537,332 and 6,712,497. DE 8915 094 relates to a refrigerated pot for dispensing a milk-basedbeverage. U.S. Pat. No. 3,356,349 discloses a stirring device that has aheated tank, magnetic drive means positioned under the tank for drivinga hub located in the middle of the tank.

An improved appliance for preparing froth from a milk-based liquid ormilk has been proposed in WO 2006/050900, WO 2008/142154, WO 2011/039222and WO 2011/039224. The device has: an inner tank for receiving theliquid that is to be frothed, in which a rotatable stirrer ispositioned; an outer stand holding the tank; drive and control meanswhich are in a cavity located between the inner tank and the outerstand, and which communicate with a switch and electrical connectionslocated on the outer surface of the stand; and disturbance means tooptimise circulation of the milk during frothing. In WO 2010/023313 asteam source is associated with the stirring effect.

More recently, it has been proposed, as described in WO 2009/074555 andWO 2011/144647, to provide a coffee machine with this type of milkconditioning tank.

SUMMARY OF THE INVENTION

It is a preferred object of the present invention to provide a machinefor homogenizing a food substance, such as frothing milk or a milk-basedsubstance.

It is a preferred object of the present invention to provide a machinefor heating a food substance which provides a more reliable heatmanagement configuration.

Another preferred object of the present invention is to provide ahygienic machine for heating a food substance.

A further preferred object of the present invention is to provide amachine with an improved mechanical food conditioning of the foodsubstance with or without heating, with or without cooling, of the foodsubstance during conditioning.

The invention thus relates to a machine for homogenising a foodsubstance, such as frothing milk or a milk-based substance.

The machine can be a standalone machine or a machine incorporated in afood processor such as a beverage maker e.g. a coffee maker.

The machine may be a standalone machine, e.g. directly pluggable to themains via an electric cord, or may be integrated in a food processorarranged to process other food items or to carry out different foodconditioning processes, the food processor itself being generallypluggable to the mains via an electric cord whereas the machine is asub-part of the food processor. Such a food processor may be a beveragemaker, such as a coffee maker, e.g. a beverage maker configured toprepare a beverage (such as coffee) from an ingredient capsule.

The machine of the invention may advantageously be configured to frothand/or heat and/or cool milk and optionally be associated, as astandalone machine or as an integrated machine, into a coffee maker.Standalone and integrated associations of milk frothing machines andcoffee makers are for example disclosed in WO 2006/050900, WO2008/142154, WO 2009/074555, WO 2010/023312 and WO 2010/023313.

Hence, the machine can be a milk frother which operates by incorporatingfinely divided gas bubbles, e.g. air bubbles, into milk. When themachine is configured for incorporating gas bubbles into the milk, itmay include an operating mode without incorporation of gas bubbles.

The machine includes a container having a side wall and a bottom walldelimiting a cavity.

The container may be generally cup-shaped or bowl-shaped orcylinder-shaped, the sidewall being generally upright and the bottomwall being generally flat or curved.

The container can be provided with a thermally insulating outsidematerial and/or with a handle, for seizure and optional displacement ofthe container by a human hand. Such a configuration is particularlyadvantageous when the food is processed at a higher temperatureexceeding e.g. 50° C. or below 10° C.

The container may be provided with an optional lid for confining thefood substance within the cavity.

The container can be mechanically passive. Hence, beyond the inherentmechanical properties of the materials making its structure forcontaining the food substance and for being integrated or assembled inthe machine, the container may be free of any mechanically active partsuch as a motor or movement transformation system which may requirespecial care for hygiene or cleaning purposes.

The container can be electrically passive. Hence, beyond the inherentelectric properties of the materials making its structure for containingthe food substance and for being integrated or assembled in the machine,the container may be free of any electric active parts such as anelectric circuit of discrete or integrated components (e.g. resistors,inductances, transistors, . . . ) that require special care for hygieneor cleaning purposes.

By providing a container which is mechanically and/or electricallypassive (optionally with a lid that is equally passive), it can easilybe cleaned, e.g. in a dishwater, without any risk of damaging electricand/or mechanic components.

The machine has an impeller comprising an impelling member forming animpelling surface that is drivable in rotation about a central axialdirection of the impelling surface for imparting a mechanical effect tothe food substance in the container so as to homogenise different phasesin the food substance.

For instance, the impelling surface extends over a predominant part of abottom wall delimiting the cavity, such as an impelling surface having asurface area that is greater than 75 or 85% of the cavity's bottom wall.

The machine comprises a module which has a housing means that containsan inner chamber and that delimits a seat. When the machine isintegrated in a food processor, e.g. a beverage maker such as a coffeemachine, the machine's module may be integrated into the food processorwhereas the container can be fixed to the module or removably mountedthereto.

The seat may be generally planar or cylindrical or cup-shaped. Thecontainer can be mounted, such as removably mounted, in or on this seat.

The container can be mounted, such as removably mounted, on or in theseat. The container may be assembled to or on the seat or simply placedon or in the seat. For instance, the container is removable from theseat for normal operation, e.g. to dispense the food substance, e.g.milk, from the container. The container can be removable from the seatfor servicing or maintenances purposes only.

The chamber contains one or more electric components that include anelectric motor for driving the impelling member in the container. Theelectric components may include a control unit and/or a power managementunit.

Typically, such control unit is in data-communication with auser-interface for the input of user-requests corresponding to drivingthe impeller and/or other processes such as cooling and/or heating thecontainer. The user interface can include one or more user-selectors,e.g. push and/or turn buttons, a touch-screen, touch-pad, etc.

The electric motor has an output drive axis with a driver deviceconfigured to drive in the container a follower device of the impeller.

The control unit, when present, may be programmed or otherwiseconfigured to carry out one or more heating and/or cooling and/ormechanical conditioning profiles (e.g. using the impeller) on the foodsubstance on request of a user. The control unit may for instance beassociated with a memory device for storing the different programs thatcan be carried out by the control unit.

The driver device and the follower device may be configured to rotateabout the central axial direction.

The driver device and the follower device are magnetically coupledthrough a sidewall and/or bottom wall of the container. The magneticcoupling force can be in the range of 3 to 50 such, as 5 to 25, e.g. 10to 15 N.

The driver device comprises a magnetic field-generating element that isarranged to be magnetically coupled to a corresponding ferromagnetic ormagnetic field-generating element of the follower device. Alternatively,the follower device comprises a magnetic field-generating element thatis arranged to be magnetically coupled to a corresponding ferromagneticelement of the driver device.

In accordance with the invention, the follower device extends:

-   -   over a predominant part of the bottom wall of the container, the        follower device extending typically over at least 75 or 85% of a        surface area of the bottom wall, the follower device having for        instance the general shape of a plate, e.g. disc, extending over        the bottom wall and generally in parallel thereto; or    -   across a substantial part of the bottom wall along a diameter        thereof, the follower device extending typically over at least        75 or 85% of a diameter of the bottom wall, the follower device        can be an elongated generally rod-shaped or bar-shaped member        (e.g. extending along the bottom wall's diameter) or be formed        of a plurality of such elongated members (e.g. up to 6 or 10) in        a star arrangement.

The driver device extends:

-   -   over a predominant part of a bottom part of the seat, the driver        device extending typically over at least 75 or 85% of a surface        area of the bottom part, the driver device having for instance        the general shape of a plate, e.g. disc, extending over the        bottom part and generally in parallel thereto; or    -   across a substantial part of the bottom part of the seat along a        diameter thereof, the driver device extending typically over at        least 75 or 85% of a diameter of the bottom part, the driver        device can be an elongated generally rod-shaped or bar-shaped        member (e.g. extending along the bottom wall's diameter) or be        formed of a plurality of such elongated members (e.g. up to 6        or 10) in a star arrangement.

The magnetic field generating element(s) and, when present, theferromagnetic element(s) are positioned at extremal or peripheral partsof the follower device and of the driver device.

In such a configuration of the field generating element(s) and (whenpresent) of the optional ferromagnetic element(s), the torquetransmission between the driver and follower devices via such elementscan be maximised. This is particularly advantageous when the impellerhas a high inertia and/or is exposed to a significant resistance, e.g.when the contact surface between the impeller and the food substance ishigh.

These elements may face each other via the sidewall and/or bottom wallof the container and optionally via the housing means. These elementscan face each other via:

-   -   the bottom wall along a coupling axis that is generally parallel        to the central axial direction; and/or    -   the sidewall along a coupling axis that is generally orthogonal        to the sidewall, such as a coupling axis that intercepts the        central axial direction.

The magnetic field-generating element(s) can comprise(s) anelectromagnet element or a permanent magnet element, e.g. made of atleast one of iron, nickel, cobalt, rare earth metals, e.g. lanthanide,and alloys and oxides containing such metals as well as polymers (e.g.plastics) carrying such elements and components.

The ferromagnetic element(s) may be made of at least one of Co, Fe,Fe₂O₃, FeOFe₂O₃, NiOFe₂O₃, CuOFe₂O₃, MgO Fe₂O₃, Nd₂Fe₁₄B, Mn, Bi, Ni,MnSb, MnOFe₂O₃, Y₃Fe₅O₁₂, CrO₂, MnAs, Gd, Dy, EuO, Cu₂MnAl, Cu₂MnIn,Cu₂MnSn, Ni₂MnAl, Ni₂MnIn, Ni₂MnSn, Ni₂MnSb, Ni₂MnGa, Co₂MnAl, Co₂MnSi,Co₂MnGa, Co₂MnGe, SmCo₅, Sm₂Co₁₇, Pd₂MnAl, Pd₂MnIn, Pd₂MnSn, Pd₂MnSb,Co₂FeSi, Fe₃Si, Fe₂VAl, Mn₂VGa and Co₂FeGe.

Electromagnetic elements may be used to control the position and/or theorientation of the impeller in the container.

The driver device can directly face the sidewall and/or bottom wall ofthe container.

The driver device may face indirectly the sidewall and/or bottom wall ofthe container via a housing inner sidewall and/or inner bottom walldelimiting the seat.

The impeller can have, further to the impelling member, a foot forspacing the impelling member above a bottom wall of the container, suchas a foot spaced under the impelling member by a distance in the rangeof 0.5 to 2.5 cm e.g. 1 to 2 cm.

The impeller may have a foot that has a downwardly-oriented convexcurved contact surface, e.g. a downwardly projecting pin, such that theimpeller rests on the bottom wall entirely via this convex curvedcontact surface. The convex curved contact can be in contact with thebottom wall over a total surface area of typically less than 5 mm², suchas less than 4 e.g. less than 3 for instance less than 2 for exampleless than 0.3 mm².

The contact surface can be made of hard polymeric material, such as hardplastic, or of food-safe stainless steel and be supported by a surfaceof the bottom wall made of ceramic material, such as PTFE, or offood-safe stainless steel e.g. AiSi 304 steel.

The impeller can be maintained in equilibrium on the downwardly-orientedconvex curved contact surface:

-   -   as a pendulum, by having its centre of gravity located        vertically below the contact surface; or    -   as an inverted pendulum, by having its centre of gravity located        vertically above the contact surface and by being balanced by        magnetic forces, e.g. by a self-adapting magnetic stabilising        arrangement including for instance the magnetic field-generating        element, and/or by being driven in rotation as a spinning top.

The impeller may have a foot that has the follower device.

The impelling surface may generally be disc-shaped or conically-shapedor shaped as a star.

The impelling surface can have at least one part protruding or recessedin a direction parallel to the axial direction, such as a part undulatedalong a circular direction about the axial direction or a surface with agenerally upright radial protruding or recessed part.

The impelling member, especially when provided with a disc-shaped orconically-shaped impelling surface, may have at least one opening whichextends through the member from the impelling surface to an oppositesurface of the member. The opening can be a bubble refiner opening, suchas an opening for refining gas bubbles contained in the food substanceby dividing gas bubbles contained in the food substance, e.g. dividingair bubbles contained in milk.

Such opening can be delimited by at least one portion that has along theopening an orientation which is angled away from a direction of movementof the portion when the impelling surface is driven in rotation aboutthe central axial direction. For instance, the orientation is orthogonalto the direction of movement.

The opening may be confined by a notional circular sector defined on thedisc-shaped or conically-shaped impelling surface and extend to theopposite surface.

Such sector may extend over an angle in the range of 1 to 359°, such as5 to 270°, e.g. 15 to 180° for instance 30 to 90°.

Portions of the member that are adjacent to radii defining the sectorand that delimit the opening may be configured to part gas bubblescontained in the food substance when the gas bubbles extend into orthrough the opening while the impelling surface is driven in rotation.

At least one opening can have a generally arched shape, e.g. a generalshape of a kidney or bean, such as a shape extending around the centralaxial direction.

At least one opening may have a generally circular shape, such as acircular shape that is located off the central axial direction.

At least one opening can have a generally oval or elliptic shape, suchas a shape extending radially on the member.

At least one opening may have a generally polygonal shape such as ashape that is located off the central axial direction.

At least one opening can extend as (an) individual opening(s) from aposition adjacent to the central axial direction to a position adjacentto a peripheral perimeter of the member.

At least one opening may be located next to the central axial direction.

At least one opening can be located on the central axial direction.

A plurality of openings may form an openwork of two or more spacedopening. The openings can be angled apart about the central axialdirection. The openings may be contained within and radially extend overdifferent juxtaposed or overlapping notional annulus which togetherextend substantially uninterruptedly over an overall notional continuousannulus.

The module and the follower device can each be provided with a removalmagnetic field-generating element, such as removal elements that faceeach other via the bottom wall of the container and optionally via thehousing means. The removal elements may be mounted in a mutuallyrepulsive orientation to facilitate a separation of the follower devicefrom the driver device.

The removal elements may face each other along an axis that is collinearwith or generally parallel to the central axial direction. For instance,the removal elements comprise a pair of removal elements facing eachother along the an axis that is collinear with the central axialdirection.

The removal elements can generate together such a repulsive force thatseparating the follower device from the driver device (when magneticallycoupled in the machine) requires a maximum force that is less than 15 N,such as less than 10 N, e.g. less than 5 N. This maximum force resultsfrom the difference between the (greater) overall coupling force and the(smaller) overall removal force.

The magnetic removal force itself (generated by the removal elements)can be in the range of 2 to 40 such, as 4 to 30, e.g. 8 to 15 N.

The module and the follower device may be provided with a plurality ofpairs of such removal magnetic field-generating elements that aremounted in mutually repulsive orientation, optionally mounted about thecentral axial direction.

The removal element of the module can be located in or on: the driverdevice and/or the housing means.

For example, the removal magnetic field-generating elements act inmutual repulsion along or in parallel to the rotation axis of the driverdevice and follower device. The magnetic field-generating element(s)(and when present the ferromagnetic element) for coupling the driver andthe follower devices can work in attraction along or in parallel to therotation axis to transmit a transmission torque about the rotation axiswhen the driver device is moved in rotation whereby the follower deviceis driven magnetically to follow the driver device. In such a case therepulsive elements act against the attraction of the coupling elementsalong the rotation axis without significantly reducing the attraction ofthe coupling elements about the rotation axis (i.e. the torquetransmission). Such a configuration leads to the transmission of a hightorque between the driver device and the follower device, especiallywhen the magnetic coupling elements are located at extremal positions ofthe driver and follower devices, while limiting the mutual attractionbetween the driver and follower devices (reduced by the presence of theremoval elements.

The use of such removal elements is particular advantageous whenelements or relatively strong mutual attraction or retention are used totransmit a drive action from a motor to the impeller. Such removalelements can be oriented to separate the impeller from the container ina direction that is orthogonal to the movement (e.g. rotation) of theimpeller in the container. Hence, the force (e.g. torque) for drivingthe impeller is not or significantly not affect by the removal elementsthat act against maintaining the impeller in the container.

The electric components can comprise one or more generators for heatingand/or cooling the food substance in the container. The generator may becontrolled by a control unit according to a processing program of thefood substance, such as a program for driving the impeller with orwithout heating or cooling via the generator.

The one or more electric components can include an active coolingdevice, such as a refrigerating device, for cooling the food substancein the container. This cooling device may be activated and/ordeactivated while driving the impeller.

The or at least one of the generators can be configured to generate anoscillating electromagnetic field directed to the container for heatingthe food substance in the container.

The generator can be configured to induce an electric heating current inan inductively heatable component of such machine, the inductivelyheatable component having a surface for radiating heat into the cavity.The component can be located in the cavity or form a wall of thecontainer, whereby the component surface delimits the cavity. Thecomponent may be made of aluminium or food-safe stainless e.g. AiSi 304.The generator may include at least one induction coil, such as aninduction coil located adjacent to the separation section.

The generator may be configured to emit microwaves for generatingheating microwaves directly in the food substance in the container. Sucha microwave generator can operate according to the known principles asfor example known in the food heating technology, e.g. microwave ovens.The container can made of electrically non-conductive glass or polymericmaterial.

The machine of the invention can include a control system (e.g.contained in the control unit) of the heating and/or coolinggenerator(s) for:

-   -   carrying out different heating/cooling profiles over time and/or        for carrying out one or more heating/cooling profiles of        constant or variable heating/cooling; and/or    -   disabling the heating/cooling.

At least one of the above one or more electric components may radiateheat within the chamber when electrically powered. The heat may begenerated by an electric resistance of the component.

The housing means can have a separation section and an outside sectiondistinct from the separation section, the separation section and theoutside section delimiting at least part of the chamber. The separationsection may separate the chamber from the seat. The outside section canbe separated from the seat by the chamber. The separation section andthe outside section may have such respective thermal conductivities asto promote an evacuation of the heat radiated within the chamber outsidethe module via the outside section rather than into the container viathe separation section.

The separation and the outside sections can be such that the ratio ofheat evacuated via the outside section over heat evacuated via theseparation section is of more than 2 such as at least 4 e.g. at least 9.

By providing a preferential heat evacuation path (via the outsidesection) from the module chamber to minimise a transfer of such heatinto the container, the heat generated in the container originatesmainly from the electromagnetic field directed to the container by thegenerator and is not or only insignificantly influenced by the heatgenerated within the module's chamber. Consequently, the heat generationdepends predominantly on an appropriate control of the generator (ratherthan on unwanted heat generated within the chamber). As a corollary,when the generator is switched off because no heating is temporarilydesired in the container (or when the container is actively cooled, whensuch feature is available), the container is not (or onlyinsignificantly) exposed to unwanted heat from within the chamber.Indeed such unwanted heat is predominantly evacuated via the outsidesection to outside the machine rather than via the separation sectioninto the seat and then into the container.

The separation section may surround at least partly the seat, theseparation section forming for instance an upright wall surrounding theseat and/or a trough or platform delimiting a bottom of the seat.

The housing means may include a joining section that joins theseparation section to the outside section, such as a joining sectionforming an outer sidewall of the housing means. The joining section maycomprise the below-mentioned lateral section or may be a furthersection.

The outside section can form a base or foot of the housing means.

The housing means can include a lateral section extending laterally downalong an edge of the outside section, such as a lateral section havingone or more through openings for passing heat evacuated via the outsidesection from under the outside section to laterally outside the housingmeans.

The housing means may include a lateral section extending laterally downto above an edge of the outside section, the outside section havingoptionally one or more evacuation channels for passing heat evacuatedvia the outside section underneath the lateral section to outside thehousing means.

The outside section may include a cooling device such as at least one ofa radiator, a dissipator, e.g. a ventilator, and a heat sink. Thecooling device may have a plurality of protrusions and recesses forminga surface for thermal exchange between the chamber and outside suchmachine. Such a cooling device can be different from a cooling devicefor cooling the food substance in the container.

The chamber can have a first chamber (e.g. sub-chamber) containing atleast one of the electric motor, a control unit and a power managementunit, such as a base chamber or a chamber below the seat.

The chamber may have second chamber (e.g. a sub-chamber) containing aheating and/or cooling generator, such as an upper chamber e.g. achamber formed around the seat.

The first and second chambers can be separated by a partition section ofthe housing means.

The second chamber may be adjacent to the seat via the housing means.The first chamber can be distant to the seat or adjacent thereto via thehousing means.

The machine can include a further food phase homogenisation devicecomprising at least one of:

-   -   an expansion chamber such as a venturi chamber, e.g. as        disclosed in WO01/26520 and WO2012/097916;    -   a static mixer, e.g. as disclosed in WO2012/097916; and    -   a couette flow device, e.g. as disclosed in WO2014/096183.

The further food phase homogenisation device can be located at an outletof the container.

The further food phase homogenisation device may operate with steamand/or air in combination with said food substance e.g. milk.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the schematicdrawings, wherein:

FIG. 1 is a cross-sectional perspective view of a machine having animpeller and a container according to the invention, the container beingfor instance mounted in a module;

FIG. 1a is an enlarged cross-sectional view of the central bottom partof the container of FIG. 1 when resting on the module of FIG. 1;

FIG. 2 is a cross-section of the module of FIG. 1 without container;

FIG. 3 is an external view of the module of FIG. 1;

FIG. 4 shows an outside section of the module of FIG. 1 which outsidesection is configured for evacuating heat outside the module;

FIGS. 5 to 7 illustrate different impellers that can be placed into thecontainer of FIG. 1 for imparting a mechanical effect to a foodsubstance container in the container; and

FIGS. 8 and 9 schematically illustrate two different configurations ofthe impeller resting in the container.

DETAILED DESCRIPTION

FIGS. 1 to 4 illustrate an embodiment of a machine 1 for homogenising afood substance, such as frothing milk or a milk-based substance. FIGS. 5to 7 illustrate different impeller surfaces for imparting a mechanicaleffect to the food substance. FIGS. 8 and 9 illustrate different footarrangements and magnetic arrangements of an impeller and module.

Machine 1 can be a standalone machine or a machine incorporated in afood processor such as a beverage maker e.g. a coffee maker.

Machine 1 includes a container 10, such as a mechanically and/orelectrically passive container 10, having a side wall 11 and a bottomwall 12 delimiting a cavity 10′.

Container 10 can be generally cup-shaped or bowl-shaped orcylinder-shaped, sidewall 11 being generally upright and bottom wall 12being generally flat or curved.

Container 10 may be provided with a thermally insulating outsidematerial 10″ and/or with a handle, for seizure and optional displacementof container 10 by a human hand.

Machine 1 has an impeller 30 comprising an impelling member 31 formingan impelling surface 31′,31″,31′″ that is drivable in rotation r about acentral axial direction 30′ of impelling surface 31′,31″,31′″ forimparting a mechanical effect to the food substance in container 10 tohomogenise different phases in the food substance. Impelling surface31′,31″,31′″ may extend over a predominant part of bottom wall 12.Impelling surface 31′,31″,31′″ can have a surface area that is greaterthan 75 or 85% of bottom wall 12.

Machine 1 includes a module 20 which has a housing means 22′ thatcontains an inner chamber 22,22 a and that delimits a seat 21, such as agenerally planar or cylindrical or cup-shaped seat 21, on or in whichcontainer 10 is mounted, such as removably mounted. Chamber 22,22 acontains one or more electric components 23,24,25,26 that include anelectric motor 24 for driving impelling member 31 in container 10.Electric components 23,24,25,26 may include a control unit 25 and/or apower management unit 26.

Electric motor 24 can have an output drive axis 24′ with a driver device24″ configured to drive in container 10 a follower device 35 of impeller30. Driver device 24″ and follower device 25 may be configured to rotateabout central axial direction 30′. Driver device 24″ and follower device35 are magnetically coupled through a sidewall 11 and/or bottom wall 12of container 10.

Driver device 24″ may have a magnetic field-generating element 24 a thatis arranged to be magnetically coupled to a corresponding ferromagneticor magnetic field-generating element 36 of follower device 35.Alternatively, follower device 24″ can have a magnetic field-generatingelement 36 that is arranged to be magnetically coupled to acorresponding ferromagnetic element 24 a of driver device 35.

Follower device 35 extends: over a predominant part of bottom wall 12,follower device 35 extending typically over at least 75 or 85% of asurface area of bottom wall 12; or across a substantial part of thebottom wall 12 along a diameter thereof, follower device 35 extendingtypically over at least 75 or 85% of a diameter of the bottom wall.

Driver device 24 extends: over a predominant part of bottom part of seat21, driver device 24 extending typically over at least 75 or 85% of asurface area of the bottom part; or across a substantial part of thebottom part of seat 21 along a diameter thereof, driver device 24extending typically over at least 75 or 85% of a diameter of the bottompart.

Magnetic field generating element(s) 24 a,36 and, when present,ferromagnetic element(s) 24 a,36 are positioned at extremal orperipheral parts of follower device 35 and of driver device 24″.

Elements 24 a,36 can face each other via sidewall 11 and/or bottom wall12 of container 10 and optionally via housing means 22′. For instance,elements 24 a,36 face each other via:

-   -   bottom wall 12 along a coupling axis 30″ that is generally        parallel to central axial direction 30′; and/or    -   the sidewall along a coupling axis that is generally orthogonal        to the sidewall, such as a coupling axis that intercepts the        central axial direction.

The magnetic field-generating element(s) 24 a,36 may include anelectromagnet element or a permanent magnet element, e.g. made of atleast one of iron, nickel, cobalt, rare earth metals, e.g. lanthanide,and alloys and oxides containing such metals as well as polymers (e.g.plastics) carrying such elements and components.

Ferromagnetic element(s) 24 a,36 can be made of at least one of Co, Fe,Fe₂O₃, FeOFe₂O₃, NiOFe₂O₃, CuOFe₂O₃, MgO Fe₂O₃, Nd₂Fe₁₄B, Mn, Bi, Ni,MnSb, MnOFe₂O₃, Y₃Fe₅O₁₂, CrO₂, MnAs, Gd, Dy, EuO, Cu₂MnAl, Cu₂MnIn,Cu₂MnSn, Ni₂MnAl, Ni₂MnIn, Ni₂MnSn, Ni₂MnSb, Ni₂MnGa, Co₂MnAl, Co₂MnSi,Co₂MnGa, Co₂MnGe, SmCo₅, Sm₂Co₁₇, Pd₂MnAl, Pd₂MnIn, Pd₂MnSn, Pd₂MnSb,Co₂FeSi, Fe₃Si, Fe₂VAl, Mn₂VGa and Co₂FeGe.

Driver device 24″ may face directly sidewall 11 and/or bottom wall 12 ofcontainer 10.

Driver device 24″ can face indirectly sidewall 11 and/or bottom wall 12of container 10 via a housing inner sidewall and/or inner bottom wall22″ delimiting seat 21.

Impeller 30 may have, further to impelling member 31, a foot 35,38 forspacing impelling member 31 above bottom wall 12 of container 10. Foot35,38 may be spaced under impelling member 31 by a distance d in therange of 0.5 to 2.5 cm e.g. 1 to 2 cm.

Impeller 30 can have a foot 35,38 that has a downwardly-oriented convexcurved contact surface 38, e.g. a downwardly projecting pin 38, suchthat impeller rests on bottom wall 12 entirely via convex curved contactsurface 38. Convex curved contact can be in contact with bottom wall 12over a total surface area of typically less than 5 mm², such as lessthan 4 e.g. less than 3 for instance less than 2 for example less than0.3 mm².

For instance, contact surface 38 is made of hard polymeric material,such as hard plastic, or of food-safe stainless steel and is supportedby a surface of bottom wall 12 made of ceramic material, such as PTFE,or of food-safe stainless steel e.g. AiSi 304 steel.

Impeller 30 may be maintained in equilibrium on downwardly-orientedconvex curved contact surface 38:

-   -   as a pendulum, by having its centre of gravity Gl located        vertically below contact surface 38 (FIG. 8); or    -   as an inverted pendulum, by having its centre of gravity Gh        located vertically above contact surface 38 and by being        balanced by magnetic forces, e.g. by a self-adapting magnetic        stabilising arrangement including for instance magnetic        field-generating element 24 a,36, and/or by being driven in        rotation as a spinning top. See FIG. 9.

Motor 24 of the embodiments schematically illustrated in FIGS. 8 and 9can be a motor formed of a sole stator driving the follower device as arotor or a motor with an output axis having a driving device driving thefollower device.

Impeller 30 may incorporate follower device 35.

Impelling surface 31′,31″,31′″ can be generally disc-shaped orconically-shaped or shaped as a star. Impelling surface 31′,31″,31′″ mayhave at least one part 31′,31″,31′″ protruding or recessed in adirection parallel to axial direction 30′, such as a part 31′,31″undulated along a circular direction about axial direction 30′ or asurface with a generally upright radial protruding or recessed part31′″.

Impelling member 31 may have at least one opening 31 a,31 b 1,31 b 2,31b 4,31 b 4,31 c,31 c′,31 d 1,31 d 2 which extends through member 31 fromimpelling surface 31′,31″,31′″ to an opposite surface 31 ^(IV) of member31. The opening can be a bubble refiner opening 31 a,31 b 1,31 b 2,31 b4,31 b 4,31 c, 31 c′,31 d 1,31 d 2, e.g. operating by dividing gasbubbles contained in the food substance for instance to divide airbubbles contained in milk.

Opening 31 a,31 b 1,31 b 2,31 b 4,31 b 4,31 c,31 c′,31 d 1,31 d 2 can bedelimited by at least one portion 31 bx,31 by, 31 cx, 31 cy,31 cx′,31cy′ that has along opening 31 a,31 b 1,31 b 2, 31 b 4,31 b 4,31 c,31c′,31 d 1,31 d 2 an orientation 31 n which is angled away from adirection of movement 31 r of portion 31 bx,31 by, 31 cx,31 xy,31 cx′,31cy′ when impelling surface 31′,31″,31′″ is driven in rotation r aboutcentral axial direction 30′, such as an orientation 31 n that isorthogonal to direction of movement 31 r.

Opening 31 a,31 b 1,31 b 2,31 b 4,31 b 4,31 c,31 c′,31 d 1,31 d 2 may beconfined by a notional circular sector 31 x,31 y,31 z that is defined ondisc-shaped or conically-shaped impelling surface 31′,31″,31′″ and thatextends to opposite surface 31 ^(IV).

Such sector 31 x,31 y,31 z can extend over an angle in the range of 1 to359°, such as 5 to 270°, e.g. 15 to 180° for instance 30 to 90°.

Portions 31 by, 31 by, 31 cx,31 cy,31 dx,31 dy of member 31 that areadjacent to radii 31 x,31 y defining sector 31 x,31 y,31 z and thatdelimit such opening 31 a,31 b 1,31 b 2, 31 b 4,31 b 4,31 c,31 d 1,31 d2 can be configured to part gas bubbles contained in the food substancewhen the gas bubbles extend into or through opening 31 a,31 b 1,31 b2,31 b 4,31 b 4,31 c,31 d 1,31 d 2 while impelling surface 31′,31″,31′″is driven in rotation.

At least one opening 31 a can have a generally arched shape, e.g. ageneral shape of a kidney or bean, such as a shape 31 a extending aroundcentral axial direction 30′.

At least one opening 31 b 1,31 b 2,31 b 3,31 b 4 may have a generallycircular shape, such as a circular shape that is located off the centralaxial direction 30′.

At least one opening 31 c,31 c′ can have a generally oval or ellipticshape, such as a shape extending radially on the member 31.

At least one opening 31 d 1,31 d 2 may have a generally polygonal shapesuch as a shape that is located off central axial direction 30′.

At least one opening 31 c may extend as (an) individual opening(s) froma position 31 ca adjacent to central axial direction 30′ to a position31 cb adjacent to a peripheral perimeter of member 31.

At least one opening 31 a,31 b 1,31 b 2,31 b 4,31 b 4,31 c, 31 d 1,31 d2 can be located next to axial direction 30′.

At least one opening 31 c′ may be located on central axial direction30′.

A plurality of openings 31 b 1,31 b 2,31 b 3,31 b 4; 31 c, 31 c′; 31 d1,31 d 2 may form an openwork of two or more spaced openings 31 b 1,31 b2,31 b 3,31 b 4; 31 c,31 c′; 31 d 1,31 d 2. Openings 31 b 1,31 b 2,31 b3,31 b 4; 31 c,31 c′; 31 d 1,31 d 2 can be angled apart about centralaxial direction 30′. Openings 31 b 1,31 b 2,31 b 3,31 b 4; 31 c,31 c′;31 d 1,31 d 2 may be contained within and radially extend over differentjuxtaposed or overlapping notional annulus 31 ba_31 bf,31 bb_31 be, 31bc_31 bg,31 bd_31 bh; 31 da_31 dd, 31 db_31 dc which together extendsubstantially uninterruptedly over an overall notional continuousannulus 31 ba_31 bb; 31 da_31 db.

Module 20 and follower device 35 can each be provided with a removalmagnetic field-generating element 24′″,37, such as removal elements24′″,37 that face each other via bottom wall 12 of container 10 andoptionally via housing means 22′. Removal elements 24′″,37 can bemounted in a mutually repulsive orientation to facilitate a separationof follower device 35 from driver device 24″.

Removal elements 24′″,37 may face each other along an axis 30′ that iscollinear with or generally parallel to central axial direction 30′,removal elements 24′″,37 comprising for instance a pair removal elements24′″,37 facing each other along an axis 30′ that is collinear withcentral axial direction 30′.

Removal elements 24′″,37 can generate together such a repulsive forcethat separating follower device 35 from driver device 24″ whenmagnetically coupled requires a maximum force that is less than 15 N,such as less than 10 N, e.g. less than 5 N. This maximum force resultsfrom the difference between the (greater) overall coupling force and the(smaller) overall removal force.

The magnetic removal force itself (generated by the removal elements)can be in the range of 2 to 40 such, as 4 to 30, e.g. 8 to 15 N.

Module 20 and follower device 35 can be provided with a plurality ofpairs of such removal magnetic field-generating elements that aremounted in mutually repulsive orientation, optionally mounted about thecentral axial direction.

Removal element 24′″ of module 20 can be located in or on: driver device24″ and/or housing means 22′.

Electric components 23,24,25,26 may include one or more generators 23for heating and/or cooling the food substance in container 10.

Generator 23 may be controlled by a control unit 25 according to aprocessing program of the food substance, such as a program for drivingthe impeller 30 with or without heating or cooling via generator 23.

At least one generator 23 can be configured to generate an oscillatingelectromagnetic field directed to container 10 for heating the foodsubstance therein.

Generator 23 can be configured to induce an electric heating current inan inductively heatable component 11 of such machine 1. Inductivelyheatable component 11 may have a surface 11′ for radiating heat intocavity 10′. component 11 can be located in the cavity or can form a wall11 of container 10, whereby component surface 11′ delimits cavity 10′.

Generator 23 can include at least one induction coil, such as aninduction coil located adjacent to separation section 22″.

Generator 23 may emit microwaves for generating heating microwavesdirectly in the food substance in container 10.

At least one of electric components 23,24,25,26 may radiate heat withinchamber 22,22 a when electrically powered, such as heat generated by anelectric resistance of component 23,24,25,26. Housing means 22′ can havea separation section 22″ and an outside section 22′″ distinct fromseparation section 22″. The separation section and the outside sectionmay delimit at least part of chamber 22,22 a. Separation section 22′″may separate chamber 22,22 a from seat 21. Outside section 22′″ can beseparated from seat 21 by chamber 22,22 a. Separation section 22″ andoutside section 22′″ may have such respective thermal conductivities asto promote an evacuation of heat radiated within chamber 22,22 a outsidemodule 20 via outside section 22′″ rather than into container 10 viaseparation section 22″.

Separation and outside sections 22″,22′″ can be such that the ratio ofheat evacuated via outside section 22′″ over heat evacuated viaseparation section 22″ is of more than 2 such as at least 4 e.g. atleast 9.

Separation section 22″ may surround at least partly seat 21, separationsection 22″ forming for instance an upright wall surrounding seat 21and/or a trough or platform delimiting a bottom of seat 21.

Housing means 22′ may have a joining section 22 ^(IV) that joinsseparation section 22″ to outside section 22′″, such as a joiningsection forming an outer sidewall of housing means 22′.

Outside section 22′″ can form a base or foot of housing means 22′.

Housing means 22′ can include a lateral section 22 ^(IV) extendinglaterally down along an edge of outside section 22′″, such as a lateralsection 22 ^(IV) having one or more through openings 22 ^(V) for passingheat evacuated via the outside section from under outside section 22′″to laterally outside housing means 22′.

Housing means 22′ can include a lateral section 22 ^(IV) extendinglaterally down to above an edge of the outside section. For instance,the outside section has one or more evacuation channels for passing heatevacuated via the outside section underneath the lateral section tooutside housing means 22′.

Outside section 22′″ can include a cooling device such as at least oneof a radiator, a dissipator, e.g. a ventilator, and a heat sink.Optionally, the cooling device comprises a plurality of protrusions 221and recesses 222 forming a surface for thermal exchange between chamber22,22 a and outside such machine 1.

Chamber 22,22 a may have a first chamber 22 containing at least one ofelectric motor 24, a control unit 25 and a power management unit 26,such as a base chamber 22 or a chamber below seat 21.

Chamber 22,22 a may have a second chamber 22 a containing a heatingand/or cooling generator 23, such as an upper chamber e.g. a chamberformed around seat 21.

First and second chambers can be separated by a partition section 22^(V) of housing means 22′.

Second chamber 22 a can be adjacent to seat 21 via housing means 21 andfirst chamber 22 can be distant to seat 21 or adjacent thereto viahousing means 22′.

Machine 1 may incorporate a further food phase homogenisation deviceincluding at least one of:

-   -   an expansion chamber such as a venturi chamber;    -   a static mixer; and    -   a couette flow device.

Such further food phase homogenisation device can be located at anoutlet of container 10.

Such further food phase homogenisation device may operate with steamand/or air in combination with the food substance e.g. milk.

The invention claimed is:
 1. A machine for homogenising a foodsubstance, the machine comprising: a container having a side wall and abottom wall defining a cavity; an impeller comprising an impellingmember forming an impelling surface that is drivable in rotation about acentral axial direction of the impelling surface for imparting amechanical effect to the food substance in the container to homogenisedifferent phases in the food substance; and a module which has a housingthat contains an inner chamber and that defines a seat on or in whichthe container is mounted, the inner chamber containing one or moreelectric components that include an electric motor for driving theimpelling member in the container, the electric motor having an outputdrive axis with a driver device configured to drive in the container afollower device of the impeller, the driver device and the followerdevice being magnetically coupled through the sidewall and/or the bottomwall of the container, and wherein: the driver device comprises amagnetic field-generating element that is arranged to be magneticallycoupled to a corresponding ferromagnetic element of the follower device;the follower device comprises a magnetic field-generating element thatis arranged to be magnetically coupled to a corresponding ferromagneticelement of the driver device; or the driver device comprises a magneticfield-generating element that is arranged to be magnetically coupled toa corresponding magnetic field-generating element of the followerdevice; the follower device extends in a direction selected from thegroup consisting of: over a predominant part of the bottom wall of thecontainer; and across a substantial part of the bottom wall of thecontainer along a diameter thereof; wherein the driver device extends ina direction selected from the group consisting of: over a predominantpart of a bottom part of the seat; and across a substantial part of thebottom part of the seat along a diameter thereof; the driver devicecomprises a plurality of first elements, and the follower devicecomprises a plurality of second elements each respectively arranged tobe magnetically coupled to a corresponding one of the plurality of firstelements to form a plurality of pairs of such elements, wherein theplurality of first elements are magnetically coupled to thecorresponding one of the plurality of second elements through a bottomwall of the container, and wherein the plurality of first and secondelements are positioned at extremal or peripheral parts of the driverdevice and of the follower device, and the machine has a configurationselected from the group consisting of (i) the plurality of firstelements are magnetic field-generating elements, and the plurality ofsecond elements are ferromagnetic elements; (ii) the plurality of secondelements are magnetic field-generating elements, and the plurality offirst elements are ferromagnetic elements, and (iii) the plurality offirst elements are first magnetic field-generating elements, and theplurality of second elements are second magnetic field-generatingelements; and wherein the impeller comprises the follower device, andthe machine comprises the driver device.
 2. The machine of claim 1,wherein the magnetic field-generating elements each comprise anelectromagnet element or a permanent magnet element.
 3. The machine ofclaim 1, wherein the driver device faces directly the bottom wall of thecontainer or faces indirectly the bottom wall of the container via theinner bottom wall delimiting the seat.
 4. The machine of claim 1,wherein the impeller has, further to the impelling member, a foot forspacing the impelling member above the bottom wall of the container. 5.The machine of claim 1, wherein the impeller has a foot comprising: adownwardly-oriented convex curved contact surface, such that theimpeller rests on the bottom wall of the container entirely via saiddownwardly-oriented convex curved contact surface, thedownwardly-oriented convex curved contact surface being in contact withthe bottom wall of the container over a total surface area; and/or thefollower device.
 6. The machine of claim 1, wherein the impellingsurface has a surface that generally has a shape selected from the groupconsisting of: disc-shaped, conically-shaped, and shaped as a star. 7.The machine of claim 6, wherein the impelling member has at least oneopening, the at least one opening being oriented in a position selectedfrom the group consisting of: defined by at least one portion that hasalong the at least one opening an orientation which is angled away froma direction of movement of the at least one portion when the impellingsurface is driven in rotation about the central axial direction; andconfined by a notional circular sector defined on the conically-shapedimpelling surface and extending to an opposite surface.
 8. The machineof claim 7, wherein one or more of the at least one opening exhibit atleast one feature selected from the group consisting of: having agenerally arched shape; having a generally circular shape; having agenerally oval or elliptic shape; having a generally polygonal shape;extending as an individual opening from a position adjacent to thecentral axial direction to a position adjacent to a peripheral perimeterof the impelling member; being located next to the central axialdirection; being located on the central axial direction; and a pluralityof openings forming an openwork of two or more spaced openings.
 9. Themachine of claim 1, wherein the module and the follower device are eachprovided with removal magnetic field-generating elements, the removalmagnetic field-generating elements being mounted in a mutually repulsiveorientation configured to facilitate a separation of the follower devicefrom the driver device.
 10. The machine of claim 1, wherein the one ormore electric components comprise one or more generators for heatingand/or cooling the food substance in the container.
 11. The machine ofclaim 10, wherein at least one of the one or more generators isconfigured to generate an oscillating electromagnetic field directed tothe container for heating the food substance in the container.
 12. Themachine of claim 1, wherein at least one of the one or more electriccomponents radiates heat within the inner chamber when electricallypowered, the housing having a separation section and an outside sectiondistinct from the separation section, the separation section and theoutside section defining at least part of the inner chamber, theseparation section separating the inner chamber from the seat, theoutside section being separated from the seat by the inner chamber, theseparation section and the outside section having such respectivethermal conductivities as to promote an evacuation of the heat radiatedwithin the inner chamber outside the module via the outside sectionrather than into the container via the separation section.
 13. Themachine of claim 12, wherein the outside section: forms a base or a footof the housing; and/or includes a cooling device.
 14. The machine ofclaim 1, wherein the inner chamber comprises: a first inner chambercontaining at least one of the electric motor, a control unit and apower management unit; and a second inner chamber containing a heatingand/or cooling generator.
 15. The machine of claim 1, wherein thefollower device extends in a direction selected from the groupconsisting of: over at least 75% of the surface area of the bottom wallof the container; and over at least 75% of the diameter of the bottomwall of the container; and wherein the driver device extends in adirection selected from the group consisting of: over at least 75% ofthe surface area of the bottom part of the seat; and over at least 75%of the diameter of the bottom part of the seat.
 16. The machine of claim1, wherein the module and the follower device comprise a plurality ofremoval magnetic field-generating elements that are mounted in amutually repulsive orientation about the central axial direction. 17.The machine of claim 1, comprising a further food phase homogenisationdevice comprising at least one element selected from the groupconsisting of: an expansion chamber; a static mixer; and a couette flowdevice.
 18. The machine of claim 1, wherein the impelling surface has atleast one part protruding or recessed in a direction parallel to theaxial direction and has a configuration selected from the groupconsisting of (i) undulated along a circular direction about the axialdirection and (ii) generally upright.
 19. The machine of claim 1,wherein the impeller has a foot comprising: a downwardly-oriented convexcurved contact surface, such that the impeller rests on the bottom wallof the container entirely via said downwardly-oriented convex curvedcontact surface, the downwardly-oriented convex curved contact surfacebeing in contact with the bottom wall of the container over a totalsurface area of less than 5 mm²; and/or the follower device.
 20. Themachine of claim 1, wherein at least one of the one or more electriccomponents is configured to radiate heat within the inner chamber whenelectrically powered, the housing further comprising an outside sectionseparated from the seat by the inner chamber, the outside sectioncomprising at least one evacuation channel configured to pass the heatfrom the inner chamber to an outside of the housing through the at leastone evacuation channel of the outside section.